Java LinkedTransferQueue peek() Method

The peek() method of Java LinkedTransferQueue class retrieves the head of this queue, but doesn't remove it. The method returns null if this queue is empty.

Syntax:

Parameters:

Specified By:

The peek() method of LinkedTransferQueue class is specified by peek() method in interface Queue<E>.

Return value:

The peek() method returns this queue's head and if this queue is empty, it returns null.

Example 1

import java.util.concurrent.LinkedTransferQueue;  
public class LinkedTransferQueuePeekExample1 {  
    public static void main(String[] args) {  
        int capacity =100;  
        LinkedTransferQueue<String> queue = new LinkedTransferQueue<String>();  
        queue.add("Jack");  
        queue.add("Harry");  
        queue.add("Peter");  
        queue.add("Krish");  
        //peek() method will retrieve the head of the queue  
        System.out.println("Head of queue : "+queue.peek());  
        //peek() will not remove the head from the queue  
        System.out.println("        Queue : "+queue);  
    }  
}

Test it Now

Output:

Head of queue : Jack
        Queue : [Jack, Harry, Peter, Krish]

Example 2

import java.util.Queue;  
import java.util.concurrent.LinkedTransferQueue;  
class Student {  
    int marks;  
    String name;  
    public Student(int marks, String name) {  
        this.marks = marks;  
        this.name = name;  
    }  
   public String toString(){  
        return this.name+" got "+ this.marks +" marks.";  
   }  
}  
public class LinkedTransferQueuePeekExample2 {  
    public static void main(String[] args) {  
        Student student1 = new Student(97,"Harry");  
        Student student2 = new Student(87,"John");  
        Student student3 = new Student(77,"Peter");  
        int capacity =100;  
        Queue<Student> queue = new LinkedTransferQueue<Student>();  
        queue.add(student1);  
        queue.add(student2);  
        queue.add(student3);  
         for (Student xyz : queue){  
             System.out.println(xyz);  
         }  
        System.out.println();  
       System.out.println("Topper of the class is "+queue.peek().name);  
    }  
}  

Test it Now

Output:

Harry got 97 marks.
John got 87 marks.
Peter got 77 marks.

Topper of the class is Harry

Example 3

import java.util.concurrent.LinkedTransferQueue;  
public class LinkedTransferQueuePeekExample3 {  
    public static void main(String[] args) {  
        int capacity =100;  
        LinkedTransferQueue<String> queue = new LinkedTransferQueue<String>();  
        queue.add("Jack");  
        queue.add("Peter");  
        queue.add("Harry");  
        queue.add("John");  
        queue.clear();  
        String val = queue.peek();  
        System.out.println("Head of queue is : "+val);  
    }  
}

Test it Now

Output: